Witchspace - The tunnel of hyperspace in which you travel between stars​

Wings - (1.2 release)​

WSS - Weak signal source​

WW - Water world​

WWag - Wing Waggle (Tipping wings up and down a few times to wave hello)​

WZ - War zone (see CZ)​

YT - YouTube​

NEW Section
Jargon and Slang: (List to be sorted and updated soon)

Salt or Salty - When someone is not happy about something they can be called salty
GitGud - Meaning 'Get Good' used against comments that suggest something is too difficult - Example: Docking is too Hard! - GitGud commander, practice!
High Wake - Jump to hyperspace
Low Wake - Jump to supercruise
Imp - Imperial (only perjorative if spoken by a Fed)
Fed - Federal (only perjorative if spoken by an Imp)
Buckyballing - Travelling like a Buckyball racer (Starting each jump right as the cooldown from the previous jump ends, taking 44-45 seconds per jump)
Heat Damage - The inevitable consequence of Buckyballing, especially in a slow-scooping ship
Bask - show proper respect and admiration for Emperor Arissa Lavigny-Duval. Alternately, to willfully endure heat damage while Buckyballing, especially in a Gutamaya ship. The Imperial Courier is particularly notorious for basking in this sense.
Sadge - Buckyballer slang for Sagittarius A*
Discoconda - Old school slang for an Anaconda with beam laser turrets (I always thought it should be "Disconda", myself)
Lithobraking - Buckyballer slang for intentionally scraping the inside of the mailslot or some other surface to rapidly scrub speed, usually when speed docking.
Gravity Brake - (also grav brake, planet brake) = Technique of using a planet's gravity well to decelerate yourself rapidly on supercruise approach to a station.
Frag - Fragmentation Cannon
Reverski - A combat tactic in which a pilot flies backwards to keep his enemy in front of his guns (a bit oversimplified, but...)
Rat Signal - a call to the Fuel Rats for help when you didn't remember OBAFGKM
-------------------------------------------
That's it so far, please help with additions, better descriptions and corrections. Also thanks go to Riochat for the awesome update and Rankaze fot the Slag section suggestion.